Making a 14,000 sq.ft. central glass-clad sloping roof standing 22 ft. above the 5th floor concrete roof structure spanning 90 ft. over a 10,000 sq.ft. atrium ground floor space below was structurally challenging. RJC made it happen for Loblaws’ Headquarters. The structure is a 400,000 sq.ft., four-storey head office complex, which includes two identical towers linked with bridges and a 4-storey high central atrium space. It also includes 150,000 sq. ft. of below grade parking. Cast-in-place concrete was used for the office floors, structural steel and auditorium framing for the atrium. Four elegant 9' deep exposed HSS tube trusses spaced at 30' centre to centre were designed to support the roof. The self-stabilizing triangular cross sections trusses were supported on 'Y' shaped HSS tube columns and were used to provide adequate structural capacity for not only the vertical gravity loads, but also to transfer all lateral loads around the central skylight to perimeter cross bracing.